Operation counter for protector tubes



Dec. 1, 1942. o. ACKERMANN I 2,303,521v

OPERATION COUNTER FOR PROTECTOR TUBES I A Filed D80. 12, 1941 WITNESSES: INVENTOR ATTORN EY patented Dec. 1, 1942 UNITED STATES PATENT OFFICE Otto Ackermann, Irwin, Pa., assignor to Westlng house Electric & Manufacturing Company, East Pittsburgh, Pa., a corporation of Pennsylvania Application December 12, 1941, Serial No. 422,726

8 Claims.

The present invention relates to a device for indicating the number of operations of a protective overvoltage discharge device, and more particularly to an operation counter which is especially intended for use with overvoltage discharge devices of the type known as protector tubes, or expulsion tubes.

The operation counter of the present invention is especially intended for use with protective discharge devices of the type usually referred to as protector tubes, which are widely used on electrical transmission and distribution lines for protection against lightning. Protector tubes of this type consist essentially of a pair of spaced electrodes enclosed within a tube of hard fiber, or other insulating material, which is capable of evolving large quantities of substantially unionized gas in the presence of an arc, the tube being vented to permit escape of the gas. One electrode, usually the top one, is connected to the line or other apparatus to be protected through a relatively short external gap, which protects the tube from the normal line voltage and the other electrode is connected toground. When a lightning surge occurs, the external air gap and the space between the electrodes within the'tube break down, and an arc is formed between the electrodes which permits the surge to be discharged to ground. The presence of the arc within the tube causes large quantities of unq ionized gas to be evolved from the wall of the tube, and since this gas is non-conducting, it efiects interruption of the arc and thus prevents any flow of current caused by the normal voltage of the line. Since the bore of the tube within which the gas is evolved is relatively small, the gas develops rather high pressures, so that a strong blast of gas is discharged through the vent, which is usually located at the lower end of the tube.

It is often desirable to know how many operations of a protector tube have occurred in service. One reason for this is that this information provides a convenient way of estimating the amount of wear of the tube. Since gas is evolved from the inner wall of the tube each time it operates, each discharge causes a certain amount of erosion or wear of the inside of the tube, and if the inner dimensions of the tube are increased too much by this wear, its ability to interrupt discharges is impaired. Since this wear occurs on the inside of the tube, it cannot be observed by visual inspection, and a record of the number of times the tube has operated gives a convenient indica tion of about how much wear of the tube is likely to have occurred.

A comparison of the number of operations, within a given period of time, of protector tubes on different parts of a transmission or distribution system is also sometimes desired, since such a comparison affords a reliable indication of the parts of the system in which the danger from lightning is greatest, and thus indicates where the greatest degree of lightning protection is necessary. For this reason also, it is desirable to have a reliable means for indicating the number of operations of a protector tube.

The principal object of the present invention i to provide a simple and reliable device for visually indicating the number of operations of a protector tube.

Another object of the invention is to provide an operation counter for protector tubes which is of simple and inexpensive construction, and which is designed so that the number of operations indicated by the counter can easily be observed from the ground.

A more specific object of the invention is to provide an operation counter for protector tubes in which the blast of gas which is discharged from the tube when it operates is utilized to actuate the counter.

A still further object of the invention is to provide a renewable operation counter for protector tubes which can be easily and safely removed from a tube and replaced while the line to which the tube is connected is energized.

Further objects and advantages of the invention will be apparent from the following detailed description, taken in connection with the accompanying drawing, in which:

Figure 1 is a view in side elevation showing the operation counter of the present invention in position on a protector tube;

Fig. 2 is an end view of the operation counter;

Fig. 3 is a view in side elevation showing the arrangement of the mounting means for this counter;

Fig. 4 is a view in elevation showing the counter mounted on a protector tube in its initial position;

Fig. 5 is a view showing the position of the counter after three operations of the tube; and

Fig. 6 is a view showing the final position of the counter after six or more operations of the tube.

As shown in Figs. 1 and 2, the operation indicating device or counter ll] of the present invention consists of a pair of metal side members or plates H, which are generally square or rectangular, with three of the corners cut off as shown in the drawing. These side plates i l are secured together in parallel relation by means of rivets l2 and i5, and spaced apart a definite distance by means of tubular spacers l3 fitting over the rivets between the plates. Each of the side plates H has a series of small holes 14 drilled in it, these holes being arranged in an arc about the rivet i5 which serves as a pivot for the device. A series of thin plates or blades 26 is supported between the side plates ll. These plates 16 may be made of copper, or other thin sheet metal, and as shown in Fig. 2, they are formed with longitudinally extending lugs H at each end. The lugs i7 engage in the holes 54 in the side plates ll so that each pair of holes supports one end of one of the plates [6. The plates I6 are relatively thin and are loosely supported in the side plates H, so that when a blast of hot gas from a protector tube strikes one of the plates E6, the plate is readily blown out of the holes 14 and drops from between the plates H or the plate I8 may be ruptured and fall out of the device.

In order to facilitate observation from the ground of the number of operations indicated by the device, suitable indicia may be provided on one or both of the side plates i l. Thus, radial lines i8 extending towards each pair 01' holes I4 may be placed on the plates ii and numerals may be placed opposite each pair of holes which supports a single plate l6. In the embodiment shown in the drawing, there are six of the plates [6 and the numerals therefore run from zero to five, inclusive, but it will be understood that either a smaller or a larger number of plates i6 might be employed, and numbered accordingly. A strap i9 is secured to the side plates II by means of the rivets l2 at the top of the device H] in order to provide an easy means for placing the device in position and for removing it.

The operation counter Ill is adapted to be pivotally mounted adjacent a protector tube, the number of operations of which are to be indicated. Fig. 4 shows, somewhat diagrammatically, a high voltage protector tube 26 with the counter l0 mounted in position on it. The tube 20 has a downwardly extending vent pipe 2| through which the gas generated in the tube during a discharge is vented to the outside, and the tube 20 is mounted in position by suitable clamping means 22 on a support 23, which may be a cross arm of a transmission line tower or other suitable supporting structure. The mounting means for the counter I0 is shown more clearly in Fig. 3. As shown in this figure, the mounting includes a short length of pipe 24 which may be of relatively small diameter. The pipe 24 is threaded at one end, as indicated at 25, and is screwed into a hole drilled in the vent pipe 2i and internally tapped. A bracket member 26 is also provided, which may be made of strap metal, and which has a hole in one end which fits over the pipe 24. The bracket member 26 is placed against the vent pipe 2! and the pipe 24 and bracket 25 are secured in position by means of suitable nuts 21. The bracket member 26 provides a pivotal mounting for the counter IE and is bent into a hook shape at its outer end, as indicated at 28, for this purpose. The outer end of the pipe 24 is partially cut oil to provide an outwardly extending lip or stop 29, or if desired, a suitable projection may be welded to the lower part of the pipe to form the stop 29.

As shown in Fig. 1, the counter device 10 is mounted on the protector tube by engaging the rivet i5 in the hook portion 28 of the bracket 26, so that the device i0 is pivotally mounted on the bracket. The length of the pipe 24 is made such that when the rivet I5 is engaged in the hook 28, the lowermost of the series of thin plates 16 rests on the stop 29, and is thus positioned directly in front of the open end of the pipe 24. It will be apparent that the counter device (0 is readily put in place and removed, since it is mounted merely by engaging the rivet IS in the hook 28 and permitting the lowermost plate IE to rest on the stop 29. When the line to which the protector tube 20 is connected is energized, this operation can easily and safely be performed by means of a conventional hook stick, or other similar insulated device, which can be inserted in the strap 19 to lift the device off, or to place it in position. This can easily be done by a man at a safe distance of several feet away from the tube 20.

When the counter D is initially placed in position, as described above, it is in the position shown in Figs. 1 and 4, with the lowermost plate l6 resting on the stop 29 in front of the open end of the tube 24. In this position, the counter shows that there have been no operations of the tube since the counter Was mounted on it, and for this reason, the series of numbers on the side plate H starts with zero, which is placed opposite the first plate l6. When the protector tube 20 operates to discharge a lightning surge on the line, a large quantity of gas is produced inside the tube and is discharged through the vent pipe 2i. The pipe 24 is tapped into the vent pipe at a suitable location, and a portion of the escaping gas will, therefore, be discharged through the pipe 24. The lowermost plate i6 is posi tioned immediately in front of the open end of the pipe 24, and since a portion of the gas is discharged through this pipe in a blast of high velocity and relatively high temperature, the thin plate l6 will be blown out of the side plates II, or ruptured by the blast of gas. In either case, the plate IE will fall out of the device, and since the counter l6 was supported in position by this plate, the counter will then be free to move about the rivet [5 as a pivot until the next plate l6 drops into place on the stop 29. Since the discharge of gas from the tube is of short duration, the blast of gas will have practically ceased by the time the next plate drops into position, and the device i0 will remain in its new position until another discharge through the tube 20 occurs, when the same operation will be repeated, and the counter 10 will again move about its pivot 15 until the next of the series of plates l6 drops into place in front of the tube 24.

Thus, each operation of the protector tube 20 causes one of the plates Hi to be blown away, and with each operation of the tube, the counter 10 will, therefore, move around its pivot Hi to bring the next plate of the series into place against the stop 29, so that the position of the counter l0 indicates the number of operations of the tube that have occurred since the counter was mounted on it. For example, as shown in Fig. 5, after three operations of the tube, the first three of the plates IE will have been blown away, and the plate which is supported in the holes marked 3 will be resting on the stop 29. The counter device i 0 will then be in the position shown in Fig. 5, with the numeral 3 and the corresponding radial line approximately horizontal,

After all the plates [6 have been blown away by successive operations of the tube 20, the device It) will swing free about its pivot l5, and will hang down in the position shown in Fig. 6, indicating that six or more operations of the tube have occurred. When this position is reached, the counter can readily be removed by means of the strap I9, as described above, and replaced by a new one.

It should now be apparent, therefore, that a simple and reliable counter device has been procan be obtained by visual observation of the counter from the ground, and this is facilitated by the provision of suitable indicia, such as the radial lines and numerals described above, Thus,

the operation counter of the present invention has many advantages, and makes it possible to easily determine the number of operations of a protector tube.

It will be understood, of course, that various 1 changes and modifications may be made without departing from the spirit of the invention. Thus, any desired number of plates I6 may be used, although the use of six plates has been found satisfactory, since with this number of plates the device will normally not have to be replaced more often than once a year. Although a preferred embodiment of the invention has been illustrated and described, it is to be understood that the invention is not limited to the particular arrangement shown, but in its broadest aspects it includes all equivalent embodiments and modifications which come within the scope of the appended claims.

I claim as my invention:

1. A device for indicating operations of an over-voltage discharge device of the protector tube type in which the discharge is interrupted by evolution of gas within the tube, said indicating device comprising a series of thin plates, sup- 7 porting means for said series of plates, means for movably mounting said supporting means adjacent a protector tube with the first of said series of thin plates disposed in the path of gas discharged from the tube, and stop means engaging said first plate to retain said supporting means against movement, said mounting means being so arranged that when said first plate is blown away by a discharge of gas from the protector tube the supporting means moves the next plate of the series into engagement with the stop means, whereby the position of the device indicates the number of operations of the protector tube.

2. A device for indicating operations of an over-voltage discharge device of the protector tube type in which the discharge is interrupted by evolution of gas within the tube, said indicating device comprising a series of thin plates, supporting means for said series of plates, means for movably mounting said supporting means adjacent a protector tube, said mounting means including a stop which engages the first of said series of thin plates to position said first plate in the path of gas discharged from said tube, and to retain said supporting means against movement, said thin plates being adapted to be blown away by gas discharged from said protector tube, and said mounting means being so arranged that as each plate is blown away said supporting means is free to move to bring the next plate of the series into engagement with said stop, whereby the position of the device indicates the number of operations of the protector tube.

3. A device for indicating operations of an overvoltage discharge device of the protector tube type in which the discharge is interrupted by evolution of gas within the tube, said indicating device comprising a series of thin plates, supporting means for said series of plates, means for pivotally mounting said supporting means adjacent a protector tube, said series of thin plates being arcuately arranged about the pivot of said supporting means, and stop means engaging the first of said series of plates to position it in the path of gas discharged from said protector tube, and to retain said supporting means against movement about its pivot, said thin plates being adapted to be blown away by gas discharged from said protector tube, and said mounting means being so arranged that as each plate is blown away the supporting means is free to move about its pivot to bring the next plate of the series into engagement with the stop means, whereby the position of the device indicates the number of operations of the protector tube.

4. A device for indicating operations of an overvoltage discharge device of the protector tube type in which the discharge is interrupted by evolution of gas within the tube, said indicating device comprising a series of thin plates, supporting means for said series of plates, and means for mounting said supporting means adjacent a protector tube, said mounting means including a pipe adapted to be secured in said protector tube so that a portion of the gas produced when the tube operates is discharged through the pipe, said mounting means also including stop means for engaging the first of said series of plates to position it at the end of said pipe in the path of the gas discharged therethrough, and for retaining said supporting means against movement, said thin plates being adapted to be blown away by the gas discharged through said pipe, and said mounting means being so arranged that as each plate is blown away, the next one of the series moves into engagement with said stop means, whereby the position of said supporting means indicates the number of operations of the protector tube.

5. A device for indicating operations of an overvoltage discharge device of the protector tube type in which the discharge is interrupted by evolution of gas within the tube, said indicating device comprising a series of thin plates, supporting means for said series of plates, means for pivotally mounting said supporting means adjacent a protector tube, said series of thin plates being arcuately arranged about the pivot of said supporting means, said mounting means including a pipe adapted to be secured in said protector tube so that a portion of the gas produced when the tube operates is discharged through the pipe, said mounting means also including stop means for engaging the first of said series of plates to position it at the end of said pipe in the path of the gas discharged therethrough, and for retaining said supporting means against movement about its pivot, said thin plates being adapted to be blown away by the gas discharged through said pipe, and said mounting means being so arranged that as each plate is blown away the supporting means is free to move about its pivot to bring the next plate of the series into engagement with the stop means, whereby the position of the device indicates the number of operations of the protector tube.

6. A device for indicating operations of an overvoltage discharge device of the protector tube type in which the discharge is interrupted by evolution of gas within the tube, said indicating device comprising a series of thin plates, supporting means for said series of plates, means for pivotally mounting said supporting means adjacent a protector tube, said pivotal mounting comprising a bracket member having a hookshaped portion in which said supporting means is removably received, said series of thin plates being arcuately arranged about the pivot of said supporting means, said mounting means including a pipe adapted to be secured in said protector tube so that a portion of the gas produced when the tube operates discharged. through the pipe, and said mounting means also including stop means for engaging the first of said series of plates to position it at the end of said pipe in the path of the gas discharged therethrough, and for retaining said supporting means against movement about its pivot, said thin plates being adapted to be blown away by the gas discharged through said pipe, and said mounting means being so arranged that as each plate is blown away the supporting means is free to move about its pivot to bring the next plate of the series into engagement with the stop means, whereby the position of the device indicates the number of operations of the protector tube.

7. A device for indicating operations of an cvervoltage discharge device of the protector tube type in which the discharge is interrupted by evolution of gas within the tube, said indicating device comprising a pair of side members, means for securing said members in parallel relation and spacing them apart, and a series of thin plates supported between said side members, said evice being adapted for movable mounting adjacent a protector tube to bring said thin plates successively into the path of gas discharged from the tube, and said plates being adapted to be blown away by said gas.

8. A device for indicating operations of an voltage discharge device of the protector tube 11 which the discharge is interrupted by r :lution of gas within the tube, said indicating device comprising a pair of side members, securing and spacing members holding said side members in parallel relation, and a series of thin plates supported between said side members, said series of plates being disposed arcuately about one of said securing and spacing members, said device being adapted for pivotal mounting by said one securing and spacing member adjacent a protector tube to bring said thin plates successively into the path of gas discharged from the tube, and said plates being adapted to be blown away by said gas.

OTTO ACKERMANN. 

